1. Field of the Invention
The present invention relates to a control apparatus, for example, for controlling focus adjustment of an imaging apparatus performed by an operator, and an imaging apparatus equipped with the control apparatus.
2. Description of the Related Art
Conventionally, most imaging apparatuses such as a still camera and a video camera include a manual focus (MF) function of manually performing focus adjustment on an object. However, since resolution of an image is increased along with recent increase of a number of pixels of an image sensor and a high definition system, focus adjustment has to be more finely tuned when a focus is manually adjusted.
Conventionally, as an operation unit for the MF operation, a key switch that executes a key operation, a touch panel, and a rotation member such as a focus ring, a dial or a wheel have been produced.
Since only two kinds of operation amount, namely on and off, can be input by the key operation, the focus can be easily shifted at one stroke by continuously pressing the key. However, it is bothersome to perform fine focus adjustment since minute manipulation needs to be repeated for that purpose.
A ring, a wheel or the like can change the operation amount by a rotation amount and a rotation speed, so that they are suitable for the fine focus adjustment. However, if an amount of focus change responding to the operation amount is set small so as to enable the fine focus adjustment, the operation amount increases when the focus needs to be widely shifted. Consequently, it becomes difficult to quickly perform focus adjustment.
Accordingly, an ease-of-use operation unit is provided which includes both a key for rough focus adjustment and a wheel for fine focus adjustment and has advantages of both devices.
On the other hand, a recent imaging apparatus has been miniaturized in order to enhance portability. Thus, it is required to dispose a key and a wheel in an area as small as possible. Japanese Patent Application Laid-Open No. 10-148751 discusses an information input apparatus which includes a wheel and a key disposed within the wheel to decrease an area where the wheel and the key are disposed and enables performing of two types of operations with one finger.
The information input apparatus discussed in Japanese Patent Application Laid-Open No. 10-148751 enables one finger (e.g., right hand thumb) to operate both the key and the wheel. In this apparatus, in order to prevent making an unintentional operation by mistake, when any one of the key and the wheel is operated, another operation is neglected.
However, application of the above-described information input apparatus to the above-described MF operation causes a following problem. That is, if the key is unnoticeably operated by mistake at the same time that the wheel is operated to finely adjust focus, the operation of the wheel is neglected, so that an object is greatly out of focus and an MF operation cannot be performed as intended.
As described above, along with miniaturization of an imaging apparatus, a key and a wheel tend to be disposed within a small and narrow region. Thus, the above-described problem frequently occurs and operability of the MF becomes greatly impaired.